Steve Irwin, the Australian TV environmentalist, known as the Crocodile Man, was killed today by a stingray barb during a diving expedition.

Irwin, 44, was filming an underwater documentary on the Great Barrier Reef, off Queesland state when the accident occurred, police said.

Telephone calls to Australia Zoo, Irwin's zoo in southern Queensland, were not answered.

The Australian Broadcasting Corporation said Irwin was diving near Low Isles, near the resort town of Port Douglas, 1,260 miles north of Brisbane when the incident happened.

A helicopter carrying paramedics flew to the island, but he died from a stingray barb to the heart, ABC reported.

Irwin is famous for his enthusiasm for wildlife and his catchphrase Crikey! in his TV show, Crocodile Hunter, which was first broadcast in Australia in 1992 and has been shown around the world on the Discovery Channel.

He rode his image into a feature film, and developed the Australia Zoo as a tourist attraction.

The public image was dented in 2004 when Irwin triggered an uproar by holding his baby in one arm while feeding large crocodiles inside a zoo pen. Irwin claimed at the time there was no danger to his son, and authorities declined to charge Irwin with violating safety regulations.

Later that year, he was accused of getting too close to penguins, a seal and humpback whales in Antarctica while making a documentary. Irwin denied wrongdoing, and an Australian environment department probe recommended no action.